Table of Contents
Every South African citizen and permanent resident is issued a unique 13-digit identity number. This number is more than just a random sequence—it encodes important information about the individual, including their date of birth, gender, and citizenship status.
1. Structure of SA ID Numbers
South African ID numbers follow a standardised format established by the Department of Home Affairs. The 13-digit number is structured as follows:
- YYMMDD - Date of birth
- SSSS - Gender sequence number
- C - Citizenship status
- A - Deprecated digit (usually 8)
- Z - Checksum digit
2. Digit-by-Digit Breakdown
| Position | Digits | Meaning | Example |
|---|---|---|---|
| 1-2 | YY | Year of birth | 85 = 1985 or 2085 |
| 3-4 | MM | Month of birth | 01 = January |
| 5-6 | DD | Day of birth | 15 = 15th |
| 7-10 | SSSS | Gender & sequence | 5000-9999 = Male |
| 11 | C | Citizenship | 0 = SA Citizen |
| 12 | A | Deprecated (was race) | Usually 8 |
| 13 | Z | Checksum | Luhn algorithm |
3. Date of Birth (Digits 1-6)
The first six digits represent the date of birth in YYMMDD format:
- YY (digits 1-2): Last two digits of the birth year
- MM (digits 3-4): Month of birth (01-12)
- DD (digits 5-6): Day of birth (01-31)
Important: Since only two digits are used for the year, there's ambiguity between centuries. The system assumes:
- 00-24 refers to 2000-2024
- 25-99 refers to 1925-1999
This is known as the "windowing" approach and may need adjustment as we move further into the 21st century.
4. Gender Indicator (Digits 7-10)
Digits 7 through 10 form a four-digit sequence number that indicates gender:
Sequence numbers in this range indicate female
Sequence numbers in this range indicate male
This sequence number also helps differentiate between people born on the same day, as each person receives a unique sequence number within their gender range.
5. Citizenship Status (Digit 11)
The 11th digit indicates citizenship status:
- 0 - South African citizen by birth or naturalisation
- 1 - Permanent resident (not a citizen)
6. Checksum Validation (Digit 13)
The final digit is a checksum calculated using the Luhn algorithm. This mathematical formula helps detect accidental errors such as mistyped digits.
When validating an ID number, if the checksum doesn't match, the ID is definitely invalid. However, a matching checksum doesn't guarantee the ID is genuine—it only confirms the digits are in a valid format.
7. How to Validate an ID Number
To validate a South African ID number, you need to check:
- Length: Must be exactly 13 digits
- Date validity: The first 6 digits must form a valid date
- Checksum: The Luhn algorithm checksum must be valid
Use our free SA ID validator at the top of this page to instantly check any ID number.
8. Frequently Asked Questions
How many digits are in a South African ID number?
A South African ID number consists of exactly 13 digits. These digits encode the person's date of birth, gender, citizenship status, and include a checksum for validation.
Can I determine someone's age from their ID number?
Yes, the first 6 digits of a South African ID number represent the date of birth in YYMMDD format. From this, you can calculate the person's age. Our validator automatically extracts and displays this information.
What does digit 12 mean in an SA ID?
Digit 12 was historically used for racial classification during apartheid. This usage has been discontinued and the digit is now deprecated. You'll commonly see the value 8 in this position.
Is it legal to validate ID numbers?
Yes, validating the format and checksum of an ID number is legal. However, you should always handle personal information responsibly and in compliance with POPIA (Protection of Personal Information Act). Our service processes all data client-side and stores nothing.